IgG Antibody to Borrelia burgdorferi (Lyme Disease) by Immunoassay
This test measures antibodies in your blood that your immune system produces in response to *Borrelia burgdorferi*, the bacterium responsible for Lyme disease. It helps diagnose infection caused by a tick bite.
["This test checks for Lyme disease antibodies, often used after a tick exposure or early symptoms appear."]
Key facts at a glance
- LOINC
- 31314-8
- Short code
- COX2IGG
- Synonyms
- C burnet Ph2 IgG Ser Ql
- Category
- chemistry
- Sample
- serum
- Container
- Serum separator tube (SST) or red-top tube
- Units
- N/A
- Ref low
- 0
- Ref high
- 1
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- Immunofluorescence Assay (IFA)
- CPT
- 86638
- SNOMED
- 122700008
- Specimen volume
- 1-2 mL of serum
- Stability
- Stable for 7 days at 2-8°C; for longer storage, freeze at -20°C or below
- Hemolysis max
- 100
- Lipemia max
- 100
- Icterus max
- 50
- TAT
- 24–72 hours
- Order
- routine
What Does This Test Measure?
The test detects IgG antibodies specific to *Borrelia burgdorferi*, a bacterium transmitted through tick bites. These antibodies develop after the body has been exposed to the bacteria and can persist for months or years. The presence of these antibodies suggests past or ongoing infection, though they may not always indicate active disease.
Why Might You Need This Test?
Your healthcare provider may order this test if you have symptoms like fever, rash (especially a bullseye rash), joint pain, or fatigue—common signs of Lyme disease. It’s also used in cases of suspected tick exposure, especially if you live in or have traveled to areas where Lyme disease is common.
What to Expect Before the Test
No special preparation is needed. You’ll have a simple blood draw, usually taken from your arm. The blood is sent to a lab for testing using an immunoassay method, which detects the antibodies without measuring the bacteria directly.
What to Expect After the Test
Results are typically ready within a few days to a week. If antibodies are found, your provider may recommend further testing (like a Western blot) or additional follow-up to confirm Lyme disease or rule out other conditions.
Reference range
Negative: <1:16; Positive: ≥1:16. Phase 2 IgG antibodies indicate past exposure or chronic Q fever infection.N/A
No special preparation required. Fasting is not necessary.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
IgG Anti-Borrelia burgdorferi
Frequently asked questions
If your test is positive for IgG antibodies, it means your immune system has likely encountered *Borrelia burgdorferi* at some point. However, a positive result does not always mean you currently have an active infection. Your provider will consider your symptoms, medical history, and other test results to determine if treatment is needed.
Yes, a negative IgG test means you likely do not have detectable antibodies to *Borrelia burgdorferi* at this time. However, Lyme disease can sometimes be missed if tested too early (before antibodies develop) or if the infection has resolved. If you suspect you’ve been bitten by a tick or have symptoms, discuss this with your provider.
A positive IgG test alone doesn’t always mean you’re sick now. Some people develop antibodies without ever having symptoms. Your provider may recommend monitoring or additional tests to check for active infection, especially if you’ve had recent tick exposure or live in a high-risk area.
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 15, 2026. · Read our editorial policy